1. Field of the Invention
Applicant's invention relates to a flame spray system and method for applying uniform coatings of powdered plastics to surfaces. Applicant's invention utilizes a pressurized carrier gas stream, normally air or nitrogen, to transport plastic powder to a spray gun. The powder passes through a flame at the head of the spray gun, melting the powder into droplets. When the molten plastic droplets strike the application surface, they adhere and combine to form a solid coat of plastic upon cooling.
2. Background Information
Various flame spray systems for applying powdered plastic to surfaces currently exist. Yet, these systems are not utilized extensively because they have design flaws, are not adjustable to meet spray pattern requirements, and for various safety reasons.
For example, due to design flaws in many of the prior art systems, powder begins to melt before it reaches the designated melt zone. This premature melting plugs up the system, which causes extensive delays due to system down time. Additionally, many of the prior art systems utilize a pressurized hopper to store the powder. As the powder exits the prior art hopper it begins to tunnel, releasing varying quantities of powder to the spray gun which cause an unsatisfactory application. In other prior art systems, the controls for regulating the flame are very near the flame. Consequently, the user's hands come in close proximity to the very hot flame when gas adjustments are required. In many instances, due to the close proximity to the flame, the controls become hot themselves and the user is either burned by touching the controls or contacting the flame while trying to adjust the controls.
Most prior art systems lack safety features which extinguish the flame if the gun is dropped. This lack of an emergency shut-off is a major detriment to prior art systems because if scaffolding is utilized, the user must crawl down several levels of the scaffolding to retrieve the lost gun. In the time it takes to retrieve the gun, a fire may have already broken out.
The prior art systems also do not enable the user to change the flame pattern or powder position to the flame, both of which are necessary for spraying varying meshes of powder. Finally, most prior art systems are very heavy and clumsy. The spray guns are unbalanced; the controls are inaccessible; and the powder metering systems are difficult to adjust. All of which leads to lower work efficiency and increased down time.
Consequently, a need exists for a flame spray system that allows the user to regulate both the flame temperature and the powder exiting position so that different meshes and types of powder may be utilized and various spray patterns may be achieved. In addition, a flame spray system is required that has flame controls positioned such that the applicant is not burned, yet allowing the user to control and manipulate the flame without accessing numerous distant parts of the system. Finally, the system should include safety features which ensure that the flame is extinguished if the spray gun is dropped or powder is not released for a set period of time adaptable by the user.